Greetings all. I have an '84 300D turbo with 374,000 miles on it. Have sorted locks, A/C, mono-valve, etc., and the car is shaping up nicely. Car runs great but I've noticed that cruise control will "pulse" with turn signals. Running down the interstate with cruise set, use signals for lane change, and throttle pulses as the signals flash. Suggestions (apart from not signaling lane changes!) ?
Thanks. Fred Burgess

Fredmburgess,

Do you see the same result if you flash the high beams or turn the headlights and fog lights on and off? If so, you may have a weak voltage regulator or alternator.

It would seem you may be experiencing enough of a voltage droop when the blinkers light, followed by a recovery when they turn off, that the control circuit is being affected. The function of the voltage regulator is to limit these swings to levels that allow the rest of the electrical stuff to work correctly. As the regulator fails to regulate, the battery will eventually begin to weaken. Are you having any difficulty starting?

Just some thoughts. Hope it helps, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

I have a 85 300TDT, amoung others, that does the same thing, has been doing it for about a year now, works fine unless you use the turn signals, my mechanic believes it is a cruise control amplifier, mine is not that anoying, hope some one else responds would like to hear what they have to say.

Did either of you change your lamp bulbs lately? I have understood that the electrical system is very sensitive with the wattage of bulbs. They must be euro spec or it can cause problems with the cruise. I can't shed any light on this as experience, just info that I have read. .02 GOOD LUCK! CD in SC

Thanks for the suggestions. I noticed that wipers did not cause the cruise to stumble but will check high beams/fog lights. Haven't changed any bulbs but PO may have so I'll check those too. Have 600 mile drive tomorrow so there's plenty of time to run tests. fmb